A storage system is constituted from: a storage control unit for executing processing of data issued by a host computer; and storage devices for storing data. A technique for improving the reliability of the storage system by providing a plurality of storage control units described above and realizing data redundancy in storage devices is known (Japanese Patent Application Laid-Open (Kokai) Publication No. 2008-134775).
Japanese Patent Application Laid-Open (Kokai) Publication No. 2008-134775 discloses a storage system having a plurality of storage control units, wherein load is distributed by using a technique for delivering an input/output request issued by a host computer to a processor that should process the input/output request, thereby improving a data processing speed.